Organic light emitting display device and method of manufacturing the same

ABSTRACT

Disclosed are an organic light emitting display device to improve optical efficiency and prevent deterioration in reliability of thin film transistors, and a method of manufacturing the same. The organic light emitting display device includes a mirror wall which is disposed on a substrate such that the mirror wall surrounds a light emitting area of each sub-pixel where a light emitting element is disposed, thus preventing total reflection of light produced in the light emitting element and improving optical efficiency by reflecting light travelling toward a non-emitting area to be directed to the light emitting area.

This application claims the benefit of Korean Patent Application No.10-2016-0161945, filed on Nov. 30, 2016, which is hereby incorporated byreference as if fully set forth herein.

BACKGROUND

Technical Field

The present disclosure relates to an organic light emitting displaydevice and a method of manufacturing the same. More particularly, thepresent disclosure relates to an organic light emitting display deviceto improve optical efficiency and prevent deterioration in reliabilityof thin film transistors, and a method of manufacturing the same.

Description of the Related Art

Image display devices for displaying a variety of information on ascreen are significant technologies in the information-technology eraand are being developed into slimmer, lighter weight, more portable andhigher-functional forms. In response to these requirements, organiclight emitting diodes that display an image by controlling the amount oflight emitted by an organic light emitting layer attract a great deal ofattention as flat panel display devices capable of reducing weight andvolume, which are drawbacks of cathode ray tubes. Organic light emittingdiodes (OLEDs), which spontaneously emit light, have low powerconsumption, rapid response speed, high luminous efficacy, highbrightness and wide viewing angle.

Organic light emitting diodes include a light emitting element and apixel circuit which independently operates the light emitting elementand includes a plurality of transistors.

Here, when light generated in the light emitting element travels towarda substrate, total reflection occurs in an inner area between the lightemitting element and the substrate due to the difference in refractiveindex between thin films disposed between the light emitting element andthe substrate. Accordingly, the light extraction efficiency of lightemitted to the rear surface of the substrate is lowered to 20 to 35%. Inaddition, a part of light generated in the light emitting elementtravels toward a non-light emitting area, rather than a light emittingarea, thus causing deterioration in light extraction efficiency. Inaddition, when light scattered by total reflection which occurs insidethe substrate is incident upon the channel of a thin film transistorincluded in a pixel circuit, it is difficult to control on/off of thethin film transistor due to photon energy, thus disadvantageouslycausing deterioration in reliability of the thin film transistor.

BRIEF SUMMARY

Accordingly, the present disclosure is directed to an organic lightemitting display device and a method of manufacturing the same thatsubstantially obviate one or more problems due to limitations anddisadvantages of the related art.

In various embodiments, the present disclosure provides an organic lightemitting display device having improved optical efficiency and thatprevents or reduces deterioration in reliability of thin filmtransistors, and a method of manufacturing the same.

Additional advantages, objects, and features of the disclosure will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of thedisclosure. The objectives and other advantages of the disclosure may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the disclosure, as embodied and broadly described herein,provided are an organic light emitting display device which includes amirror wall which is disposed on a substrate such that the mirror wallsurrounds a light emitting area of each sub-pixel where a light emittingelement is disposed, thus preventing total reflection of light producedin the light emitting element and improving optical efficiency bycollecting light travelling toward a non-emitting area to the lightemitting area, and a method of manufacturing the same.

In one embodiment, the present disclosure provides an organic lightemitting display device that includes a substrate, a plurality ofsub-pixels on the substrate, and a reflective barrier. Each of thesub-pixels includes a light emitting element disposed in a lightemitting area, and a pixel circuit disposed in a circuit area andconfigured to operate the light emitting element. The reflective barrieris disposed overlying the substrate and surrounding a perimeter of thelight emitting area of each sub-pixel.

In another embodiment, the present disclosure provides a method ofmanufacturing an organic light emitting display device that includes:forming a pixel circuit in a pixel area of a sub-pixel on a substrate;forming a light emitting element in a light emitting area of thesub-pixel; and forming a reflective barrier on the substrate, thereflective barrier surrounding a perimeter of the light emitting area.

It is to be understood that both the foregoing general description andthe following detailed description of the present disclosure areexemplary and explanatory and are intended to provide furtherexplanation of the disclosure as claimed.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the disclosure andtogether with the description serve to explain the principle of thedisclosure. In the drawings:

FIG. 1 is a plan view illustrating an organic light emitting displaydevice according to the present disclosure;

FIG. 2 is a sectional view illustrating a sub-pixel of the organic lightemitting display device shown in FIG. 1;

FIGS. 3A and 3B are plan views illustrating embodiments of a sub-pixelof the organic light emitting display device shown in FIG. 2;

FIG. 4 is a sectional view taken along line “I-I”, of the organic lightemitting display device shown in FIGS. 3A and 3B;

FIGS. 5A and 5B are sectional views illustrating various embodiments ofa mirror wall shown in FIG. 4; and

FIGS. 6A to 6I are sectional views illustrating a method ofmanufacturing the organic light emitting display device shown in FIG. 4.

DETAILED DESCRIPTION

Reference will now be made in detail to the preferred embodiments of thepresent disclosure, examples of which are illustrated in theaccompanying drawings.

FIG. 1 is a plan view illustrating an organic light emitting displaydevice according to the present disclosure.

The organic light emitting display device shown in FIG. 1 includes anactive area AA and a pad area PA.

In the pad area PA, a plurality of pads, which each supply a drivingsignal to a scan line SL, a data line DL, a high-voltage VDD supply lineVDL and a low-voltage VSS supply line disposed in the active area AA,are formed.

The active area AA displays an image through a unit pixel including alight emitting element 130. The unit pixel includes red R, green G andblue B sub-pixels, or red R, green G, blue B and white W sub-pixels.Each of the sub-pixels includes a light emitting element 130 and a pixeldriving circuit independently operating the light emitting element.

The pixel driving circuit includes a switching transistor TS, a drivingtransistor TD and a storage capacitor Cst.

When a scan pulse is supplied to the scan line SL, the switchingtransistor TS is turned on and supplies a data signal supplied to thedata line DL to the storage capacitor Cst and a gate electrode of thedriving transistor TD.

In response to the data signal supplied to the gate electrode of thedriving transistor TD, the driving transistor TD controls a current Isupplied from the high-voltage VDD supply line VDL to the light emittingelement 130, thereby regulating the amount of light emitted by the lightemitting element 130. In addition, although the switching transistor TSis turned off, the voltage charged in the storage capacitor Cst enablesthe driving transistor TD to supply a constant current I until the datasignal of the next frame is supplied, thereby allowing the lightemitting element 130 to continuously emit light.

For this purpose, the driving transistor TD includes a gate electrode106, a source electrode 108, a drain electrode 110 and an active layer104, as shown in FIG. 2.

The gate electrode 106 is formed on the gate insulation film 112 whichis the same pattern as the gate electrode 106. The gate electrode 106overlaps a channel region of the active layer 104 such that the gateinsulation film 112 is interposed therebetween. The gate electrode 106is formed as a single layer or multiple layers using any one of Mo, Ti,Cu, AlNd, Al and Cr, or an alloy thereof, but the present disclosure isnot limited thereto. For example, the gate electrode 106 may have amultilayer stack structure of Cu/MoTi.

The source electrode 108 is connected to the active layer 104 exposedthrough a source contact hole 124S penetrating the interlayer insulationfilm 116. The drain electrode 110 is connected to the active layer 104through a drain contact hole 124D penetrating the interlayer insulationfilm 116. In addition, the drain electrode 110 is exposed through apixel contact hole 120 penetrating a protective film 118 and aplanarization layer 128 and is connected to the anode 132.

The source electrode 108 and the drain electrode 110 are, for example,formed as a single layer or multiple layers using any one of Mo, Ti, Cu,AlNd, Al and Cr, or an alloy thereof, but the present disclosure is notlimited thereto.

The active layer 104 overlaps the gate electrode 106 via the gateinsulation film 112 interposed therebetween, to form a channel betweenthe source and drain electrodes 108 and 110. This active layer 104 isformed using at least one of an amorphous semiconductor material, apolycrystalline semiconductor material and an oxide semiconductormaterial.

A buffer film 114 and a light-shielding layer 102 are formed between theactive layer 104 and the substrate 101. The light-shielding layer 102overlaps the active layer 104 on the substrate 101. Since thelight-shielding layer 102 absorbs or reflects light emitted from theoutside, it can block exterior light from entering the active layer 104.The light-shielding layer 102 is formed using a non-transparent metalsuch as Mo, Ti, Al, Cu, Cr, Co, W, Ta or Ni.

The buffer film 114 is formed as a single or multiple layer structureusing silicon oxide or silicon nitride on the substrate 101, which maybe made of glass or a plastic resin such as polyimide (PI). The bufferfilm 114 prevents diffusion of moisture or impurities in the substrate101 or controls transfer rate of heat upon crystallization, therebyfacilitating crystallization of the active layer 104.

The storage capacitor Cst is formed by a storage lower electrode 152that is overlapped by a storage upper electrode 154, with the interlayerinsulation film 116 disposed between the storage lower and upperelectrodes 152, 154. The storage lower electrode 152 is formed on thesame layer as the gate electrode 106 using the same material as the gateelectrode 106, and the storage upper electrode 154 is formed on the samelayer as the drain electrode 110 using the same material as the drainelectrode 110. The storage lower electrode 152 is connected to the drainelectrode 110 of any one of the switching transistor TS and the drivingtransistor TD, and the storage upper electrode 154 is connected to thedrain electrode 110 of the other of the switching transistor TS anddriving transistor TD. Although the switching transistor TS is turnedoff, the voltage charged in the storage capacitor Cst enables thedriving transistor TD to supply a constant current until the data signalof the next frame is supplied, thereby allowing the light emittingelement 130 to continuously emit light.

The light emitting element 130 includes an anode 132 connected to thedrain electrode 110 of the driving transistor TD, at least one lightemitting stack formed on the anode 132 and a cathode 136 formed on thelight emitting stack such that the cathode is connected to thelow-voltage VSS supply line. Here, the low-voltage VSS supply linesupplies a low-voltage VSS lower than the high-voltage VDD suppliedthrough the high-voltage supply line VDL.

The anode 132 contacts the drain electrode 110 exposed through the pixelcontact hole 120 penetrating the protective film 118 and theplanarization layer 128. The anode 132 is formed on the planarizationlayer 128 such that it is exposed in a light emitting region provided bya bank 138. That is, the bank 138 defines boundaries of the lightemitting region. In a case where the anode 132 is applied to a bottomemission type organic light emitting display device, the anode 132 isformed as a transparent conductive layer such as an indium-tin-oxide(ITO) or indium-zinc-oxide (IZO) layer.

The light emitting stack 134 is formed by stacking a hole transportlayer HTL, an organic light emitting layer EML and an electron transportlayer ETL in this order or a reverse order on the anode 132. Inaddition, the light emitting stack 134 may include first and secondlight emitting stacks 134 a and 134 b which face each other with acharge generation layer CGL interposed therebetween. In this case, theorganic light emitting layer EML of any one of the first and secondlight emitting stacks 134 a and 134 b generates blue light and theorganic light emitting layer EML of the other of the first and secondlight emitting stacks 134 a and 134 b generates yellow-green light,thereby combining to generate white light through the first and secondlight emitting stacks 134 a and 134 b.

The cathode 136 is formed on upper and side surfaces of the organiclight emitting layer 134 and the bank 138 such that the cathode 136faces the anode 132 with the organic light emitting layer 134 interposedtherebetween. In a case where the cathode 136 is applied to a bottomemission type organic light emitting display device, the cathode 136 hasa multilayer structure including a transparent conductive film and anon-transparent conductive film having high reflectivity. Thetransparent conductive film is formed using a material having a highwork-function value such as indium-tin-oxide (ITO) or indium-zinc-oxide(IZO), and the non-transparent conductive film is formed as a singlelayer or multiple layers using any one of Mo, Ti, Cu, AlNd, Al and Cr,or an alloy thereof. For example, the cathode 136 has a structure inwhich a transparent conductive film, a non-transparent conductive filmand a transparent conductive film are sequentially stacked.

The color filter 160 is disposed on the protective film 118 such thatthe color filter 160 overlaps the light emitting region provided ordefined by the bank 138. Any one of red R, green G, and blue B colorfilters is disposed in the light emitting region of each sub-pixel. Thatis, the red color filter 160 is disposed in the red R sub-pixel, thegreen color filter 160 is disposed in the green G sub-pixel and the bluecolor filter 160 is disposed in the blue B sub-pixel. Accordingly, whenwhite light generated in the light emitting stack 130 passes through thecolor filter 160, the color filter 160 renders light of the colorcorresponding to the color filter 160. Meanwhile, the color filter 160may extend so as to cover or at least partially cover at least one ofthe switching and driving film transistors TS and TD.

As such, when the light emitting stack 134 produces white light, whitelight generated in the light emitting stack 134 is incident upon thecolor filter 160, thus forming a color image. On the other hand, withoutthe color filter 148, a color image can be formed by producing light ofa color corresponding to each sub-pixel SP by each light emitting stack134. That is, the light emitting stack 134 of the red sub-pixel SP canproduce red light, the light emitting stack 134 of the green sub-pixelSP can produce green light, and the light emitting stack 134 of the bluesub-pixel SP can produce blue light.

The planarization layer 128 is formed using a transparent organicinsulation material such as an acrylic resin on the substrate providedwith the color filter 160. The planarization layer 128 serves as a whitecolor filter in the white sub-pixel region where the color filter 160 isnot formed.

Meanwhile, the present disclosure includes a reflective barrier 140which surrounds a perimeter of a light emitting area EA of eachsub-pixel, as shown in FIG. 3A, or which surrounds the perimeter of thelight emitting area EA and a perimeter of a circuit area CA, as shown inFIG. 3B.

The reflective barrier 140 includes an insulation layer 142 and areflective layer 144 disposed on the insulation layer 142. Thereflective barrier 140 may be referred to herein as a “mirror wall,” asthe reflective barrier 140 may have a mirror-like reflective surfacethat reflects light. Similarly, the reflective layer 144 may be referredto herein as a “mirror layer.” The insulation layer 142 may be referredto herein as an “insulation wall.” It should be readily appreciated thatthe insulation layer 142 or “insulation wall” may include a plurality ofwalls having a height and that surround a perimeter of one or more ofthe light emitting area EA and the circuit area CA, as described herein.

The insulation wall 142 overlaps a plurality of signal lines which crosseach other to provide respective sub-pixel areas and is disposed betweenthe light emitting area EA and the circuit area CA of each sub-pixel.For example, as shown in FIGS. 3A and 3B, the mirror wall 140 and theinsulation wall 142 may overlap a data line DL disposed along a firstdirection (e.g., in a vertical direction, as shown) and therefore facesthe left side of each of the light emitting area EA and the circuit areaCA, as shown. The insulation wall 142 overlaps a high-voltage supplyline VDL parallel to the data line DL and therefore faces the right sideof each of the light emitting area EA and the circuit area CA, as shown.The insulation wall 142 overlaps a scan line SL in a second directioncrossing the first direction (e.g., in a horizontal direction, as shown)and therefore faces the upper side of the light emitting area EA and thelower side of the circuit area CA, and the insulation wall 142 may bedisposed between the light emitting area EA and the circuit area CA andtherefore faces the lower side of the light emitting area EA and theupper side of the circuit area CA. Accordingly, the insulation wall 142surrounds the perimeter of the light emitting area EA of each sub-pixel,as shown in FIG. 3A, and the insulation wall 142 may further surroundthe perimeter of the circuit area CA of each sub-pixel, as shown in FIG.3B.

The reflective barrier or mirror wall 140, including the insulation wall142 and the reflective layer or mirror layer 142, is described herein assurrounding a perimeter of one or both of the light emitting area EA andthe circuit area CA of the sub-pixels. It should be readily appreciatedthat the mirror wall 140 may surround a perimeter of one or both of thelight emitting area EA and the circuit area CA without surrounding, forexample, a lower or upper portion of the light emitting area EA and thecircuit area CA. Further, the term surrounds a perimeter is not intendedto impart any height or width limitations, and is sufficiently broad tocover embodiments where the mirror wall 140 has a height that is lessthan, equal to, or greater than a height of portions of the lightemitting area EA and the circuit area CA that form the perimeters.

The insulation wall 142 is formed on the protective film 118, and may beformed on the same plane as the planarization layer 128, using the samematerial as the planarization layer 128. In this case, the side surfaceof the insulation wall 142 forms an acute or right angle with the uppersurface of the protective film 118.

The mirror layer 144 is formed on the side surfaces of the insulationwall 142. That is, since the side surface of the insulation wall 142overlapping the drain electrode 110 of the driving transistor overlapsthe mirror layer 144 via the anode 132, as shown in FIG. 2, the mirrorlayer 144 is connected to the anode 132. In addition, since the sidesurface of the insulation wall 142 which overlaps the signal lineincluding the data line DL, the high-voltage supply line VDL and thescan line SL overlaps the mirror layer 144 via the transparent layer146, as shown in FIG. 4, the mirror layer 144 contacts the transparentlayer 146 which is in a floating state. In particular, the mirror layer144 disposed on the signal line including the data line DL, thehigh-voltage supply line VDL and the scan line SL covers both sidesurfaces and the upper surface of the insulation wall 142, as shown inFIG. 4. In addition, in one or more embodiments, the mirror layer 144disposed on the signal line covers a part of the upper surface and theside surface of the insulation wall 142 while not overlapping the uppersurface of each signal line, as shown in FIGS. 5A and 5B. That is, themirror layer 144 may extend over only a portion of the upper surface ofthe insulation wall 142, and a portion of the insulation wall 142 thatis not covered by the mirror layer 144 may correspond with the signalline which is formed under the insulation wall 142, as shown in FIGS. 5Aand 5B.

The mirror layer 144 may be formed of any reflective material thatreflects light. The mirror layer 144 may be formed using the samematerial as the cathode 136, which may have reflectivity, or may beformed of an insulation, semiconductor or metal material havingreflectivity. For example, the mirror layer 144 may be formed as asingle layer or multiple layers using any one of molybdenum (Mo),aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni),neodymium (Nd), copper (Cu) and APC (Ag;Pb;Cu), or an alloy thereof.

The mirror layer 144 has reflectivity and therefore changes a passage oflight total-reflected through the cathode 136, thus reducing light lossdue to total reflection. In addition, the mirror layer 144 reflectslight, which travels toward the outside of the light emitting area EA,that is, toward the non-light emitting area, to the light emitting areaEA, thereby improving optical efficiency of light emitted through thelight emitting area EA of the substrate 101. In particular, the uppersurface of the mirror layer 144 disposed on the insulation wall 142 isdisposed in a higher plane, e.g., relative to a surface of the substrate101, than the lower surface of the light emitting stack 134 contactingthe anode 132. Accordingly, light which is produced from the lightemitting stack 134 and travels in a direction parallel or nearlyparallel to the length direction of the light emitting stack 136 (thatis, a direction perpendicular to the thickness direction of the lightemitting stack 136) is reflected by the mirror layer 144 and isredirected to the light emitting area EA, thereby improving opticalefficiency. Furthermore, the mirror layer 144 on the insulation wall 142disposed between the light emitting area EA and the circuit area CAreflects light, which travels toward the switching and drivingtransistors TS and TD, to the light emitting area EA, thereby preventingdeterioration in reliability of the switching and driving transistors TSand TD.

Meanwhile, the transparent layer 146 is disposed between the mirrorlayer 144 and the insulation wall 142. The transparent layer 146 isformed by the same mask process as the anode 132 and the mirror layer144. Accordingly, both ends of the transparent layer 146 correspond toboth ends of the mirror layer 144, and the transparent layer 146 isformed on the same plane as the anode 132 using the same material. Asshown in FIG. 4, the mirror layer 144 may cover the upper and sidesurfaces of the insulation wall 142, or as shown in FIGS. 5A and 5B, themirror layer 144 may cover a part of the upper surface and the sidesurface of the insulation wall 142, while not overlapping the uppersurface of each signal line.

As such, the present disclosure can prevent total reflection of lightproduced in the light emitting stack 134 and thus improve opticalefficiency because the mirror layer 144 formed on the insulation wall142 changes a route of the light produced in the light emitting stack134. In addition, the present disclosure can improve optical efficiencybecause the mirror layer 144 formed on the insulation wall 142 collectslight travelling toward the non-light emitting area to the lightemitting area. Furthermore, the present disclosure can preventdeterioration in reliability of the switching and driving transistors TSand TD because the mirror layer 144 formed on the insulation wall 142blocks light which is produced in the light emitting element 130 fromtraveling toward the switching and driving transistors TS and TD.

FIGS. 6A to 6I are sectional views illustrating a method ofmanufacturing the organic light emitting display device shown in FIG. 4.Meanwhile, the method of manufacturing the organic light emittingdisplay device shown in FIGS. 6A to 6I will be described in conjunctionwith the organic light emitting display device shown in FIG. 4 as wellas the organic light emitting display device shown in FIG. 2.

Referring to FIG. 6A, a light-shielding layer 102, a switchingtransistor TS, a driving transistor TD, a storage capacitor Cst, ahigh-voltage supply line VDL and a data line DL are formed on asubstrate 101 by five or fewer mask processes.

More specifically, the light-shielding layer 102 is formed on thesubstrate 101 by a first mask process. Here, the light-shielding layer102 is formed as a single layer using a metal material such as Mo, Ti,Cu, AlNd, Al or Cr, or an alloy thereof, or as multiple layers using thesame. A buffer film 114 is formed on the substrate 101 provided with thelight-shielding layer 102, and an active layer 104 is formed on thebuffer film 114 by a second mask process. Then, at the same time, by athird mask process, a gate insulation pattern 112 is formed on thebuffer film 114 provided with the active layer 104, and a scan line SL,a gate electrode 106 and a storage lower electrode 152 are formed on thegate insulation pattern 112. Then, an interlayer insulation film 116having source and drain contact holes 124S and 124D is formed on thesubstrate 101 provided with the scan line SL, the gate electrode 106 andthe storage lower electrode 152 by a fourth mask process. Then, a dataline DL, a high-voltage supply line VDL, a source electrode 108, a drainelectrode 110 and a storage upper electrode 154 are formed on thesubstrate 101 provided with the interlayer insulation film 116 by afifth mask process.

Then, an inorganic insulation material such as SiO_(x) or SiNx isdeposited over the entire surface of the interlayer insulation film 116provided with the data line DL, the high-voltage VDL supply line, thesource electrode 108, the drain electrode 110 and the storage upperelectrode 154 to form a protective film 118 as shown in FIG. 6B. Then,the substrate 101 provided with the protective film 118 is coated with acolored resin and the colored resin is then patterned by a sixth maskprocess to form a color filter 160.

An organic film such as a photoacrylic resin is coated over the entiresurface of the substrate 101 provided with color filter 160 and is thenpatterned by a seventh mask process, to form an insulation wall 142, aplanarization layer 128 and a pixel contact hole 120, as shown in FIG.6C.

Then, first and second conductive layers 172 and 174 and a photoresistare sequentially deposited over the entire surface of the substrate 101provided with the insulation wall 142, the planarization layer 128 andthe pixel contact hole 120, as shown in FIG. 6D. Then, an eighth mask180 having a light-shielding part 186 and a semi-transmission part 184on a mask substrate 182 is arranged on the substrate 101 provided withthe photoresist. The photoresist is patterned by a photolithographyprocess using this eighth mask to form a multi-step photoresist pattern170. In this case, the photoresist pattern 170 is formed to have a firstthickness in a region where the photoresist pattern 170 overlaps thesemi-transmission part 184 and to have a second thickness greater thanthe first thickness in a region where the photoresist pattern 170overlaps the light-shielding part 186.

Then, the first and second conductive layers 172 and 174 are patternedby an etching process using the multi-step photoresist pattern 170 as amask, to form a transparent layer 146 including the first conductivelayer 172, a mirror layer 144 including the second conductive layer 174,and an anode 132 including the first and second conductive layers 172and 174, as shown in FIG. 6E.

Then, the multi-step photoresist pattern 170 is ashed, so that thethickness of the photoresist pattern 170 having a second thickness onthe mirror layer 144 is reduced and the photoresist pattern 170 havingthe first thickness on the anode 132 is removed, to expose the secondconductive layer 174 of the anode 132, as shown in FIG. 6F. The exposedsecond conductive layer 174 is removed by an etching process using theashed photoresist pattern 170 as a mask to form the anode 132 as thefirst conductive layer 172, as shown in FIG. 6G. Then, photoresistpattern 170 remaining on the mirror wall 140 is removed by a strippingprocess. The upper surface of the mirror layer 144 is thus formed at ahigher level above the surface of the substrate 101 than the uppersurface of the anode 132 in the light emitting area.

Then, a photosensitive organic film is deposited over the entire surfaceof the substrate 101 provided with the transparent layer 146, the mirrorlayer 144 and the anode 132, and the photosensitive organic film ispatterned by a photolithography process using a ninth mask to form abank 138, as shown in FIG. 6H. A light emitting stack 134 renderingwhite light and a cathode 136 are sequentially formed on the substrate101 provided with the bank 138 by a deposition process using a shadowmask, as shown in FIG. 6I.

As such, the method of manufacturing the organic light emitting displaydevice according to the present disclosure can prevent an increase inthe number of processes because the insulation wall 142 is formed by thesame mask process as the planarization layer 128, and the mirror layer144 and the transparent layer 146 are formed by the same mask process asthe anode 132.

According to the present disclosure, the mirror wall including theinsulation wall and the mirror layer disposed on the insulation wallsurrounds the light emitting area. Accordingly, the present disclosurecan prevent total reflection of light produced in the light emittingstack and thus improve optical efficiency because the mirror layerchanges a route of the light produced in the light emitting stack. Inaddition, the present disclosure can improve optical efficiency becausethe mirror layer formed on the insulation wall reflects light travellingtoward the non-light emitting area to be redirected toward the lightemitting area. Furthermore, the present disclosure can preventdeterioration in reliability of the switching and driving transistorsbecause the mirror layer formed on the insulation wall blocks lightwhich is produced in the light emitting element from traveling towardthe switching and driving transistors.

In addition, it will be apparent to those skilled in the art thatvarious modifications and variations can be made in the presentdisclosure without departing from the spirit or scope of the disclosure.Accordingly, the embodiments described in the present disclosure are notlimited to the present disclosure. Thus, it is intended that the presentdisclosure covers the modifications and variations of this disclosureprovided they come within the scope of the appended claims and theirequivalents.

The various embodiments described above can be combined to providefurther embodiments. These and other changes can be made to theembodiments in light of the above-detailed description. In general, inthe following claims, the terms used should not be construed to limitthe claims to the specific embodiments disclosed in the specificationand the claims, but should be construed to include all possibleembodiments along with the full scope of equivalents to which suchclaims are entitled. Accordingly, the claims are not limited by thedisclosure.

What is claimed is:
 1. An organic light emitting display devicecomprising: a substrate; a plurality of sub-pixels on the substrate,each of the sub-pixels including: a light emitting element disposed in alight emitting area; and a pixel circuit disposed in a circuit area, thepixel circuit configured to operate the light emitting element; and areflective barrier disposed overlying the substrate and surrounding aperimeter of the light emitting area of each sub-pixel.
 2. The organiclight emitting display device according to claim 1, wherein thereflective barrier comprises: an insulation layer surrounding theperimeter of the light emitting area of each sub-pixel; and a reflectivelayer disposed on the insulation layer.
 3. The organic light emittingdisplay device according to claim 2, further comprising: a transparentlayer disposed between the insulation layer and the reflective layer. 4.The organic light emitting display device according to claim 3, furthercomprising: a color filter disposed between the substrate and the lightemitting element; and a planarization layer on the color filter, whereinthe insulation layer and the planarization layer are formed of a samematerial and are disposed on a same plane, and the transparent layer andan anode of the light emitting element are formed of a same material andare disposed on a same plane.
 5. The organic light emitting displaydevice according to claim 1, wherein the reflective barrier comprises:an insulation layer surrounding the perimeter of the light emitting areaand surrounding a perimeter of the circuit area of each sub-pixel; and areflective layer disposed on the insulation layer.
 6. The organic lightemitting display device according to claim 5, further comprising: atransparent layer disposed between the insulation layer and thereflective layer.
 7. The organic light emitting display device accordingto claim 5, wherein the insulating layer includes portions that extendbetween the light emitting area and the circuit area of each sub-pixel.8. The organic light emitting display device according to claim 5,further comprising: a color filter disposed between the substrate andthe light emitting element; and a planarization layer on the colorfilter, wherein the insulation layer and the planarization layer areformed of a same material and are disposed on a same plane, and thetransparent layer and an anode of the light emitting element are formedof a same material and are disposed on a same plane.
 9. The organiclight emitting display device according to claim 2, wherein thereflective layer is disposed on a side surface of the reflective barrierfacing the light emitting area.
 10. The organic light emitting displaydevice according to claim 1, wherein the reflective layer is formedusing a same material as a cathode of the light emitting element. 11.The organic light emitting display device according to claim 1, whereinthe reflective layer is formed as a single layer or multiple layersincluding at least one of molybdenum (Mo), aluminum (Al), chromium (Cr),gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu) andAPC (Ag;Pb;Cu), or an alloy thereof.
 12. The organic light emittingdisplay device according to claim 2, wherein the pixel circuitcomprises: a driving transistor connected to the light emitting element;and a switching transistor connected to the driving transistor, whereinthe reflective barrier is disposed between the light emitting area andthe circuit area.
 13. The organic light emitting display deviceaccording to claim 12, further comprising: a scan line connected to agate electrode of the switching transistor; a data line connected to asource electrode of the switching transistor; and a high-voltage supplyline connected to a source electrode of the driving transistor, whereinthe reflective barrier overlaps with the scan line, the data line andthe high-voltage supply line.
 14. The organic light emitting displaydevice according to claim 12, wherein the light emitting elementcomprises: an anode connected to the switching transistor; a cathodefacing the anode; and a light emitting stack disposed between the anodeand the cathode, wherein an upper surface of the reflective layerdisposed on the insulation layer is disposed on a higher plane relativeto the substrate than a lower surface of the light emitting stackcontacting the anode.
 15. The organic light emitting display deviceaccording to claim 14, wherein the reflective layer and the cathodereflect light produced in the light emitting stack toward the substrate.16. A method of manufacturing an organic light emitting display devicecomprising: forming a pixel circuit in a pixel area of a sub-pixel on asubstrate; forming a light emitting element in a light emitting area ofthe sub-pixel; and forming a reflective barrier on the substrate, thereflective barrier surrounding a perimeter of the light emitting area.17. The method of claim 17, wherein forming the reflective barrierincludes: forming an insulation layer surrounding the perimeter of thelight emitting area; and forming a reflective layer on at least a sidesurface of the insulating layer facing the light emitting area.
 18. Themethod of claim 17, wherein forming the reflective layer includesforming the reflective layer to have an upper surface disposed at aheight from a surface of the substrate that is greater than a height ofan anode of the light emitting element from the surface of thesubstrate.
 19. The method of claim 16, wherein forming the pixel circuitincludes: forming a driving transistor connected to the light emittingelement; and forming a switching transistor connected to the drivingtransistor.
 20. The method of claim 19 wherein forming the reflectivebarrier includes: forming at least a portion of the reflective barrierbetween the light emitting area and the pixel circuit area.